SACE Stage 2 Nutrition cheat sheet

Energy values (Atwater factors): carbohydrate 17 kJ/g (4 kcal/g), protein 17 kJ/g (4 kcal/g), fat 37 kJ/g (9 kcal/g), alcohol 29 kJ/g (7 kcal/g), dietary fibre about 8 kJ/g (2 kcal/g).

Energy from a food (kJ) = (g carbohydrate × 17) + (g protein × 17) + (g fat × 37) + (g alcohol × 29); percentage energy from a macronutrient = its kJ ÷ total kJ × 100.

AMDR (adults): carbohydrate 45–65% of energy, fat 20–35% (saturated plus trans fat under 10%), protein 15–25%; protein RDI about 0.8 g per kg body mass per day for adults.

Estimated energy requirement rises with body size, physical activity and growth; a deficit of about 37 kJ (9 kcal) per kg body mass per day approximates 1 kg of fat loss, but real loss is slower because of adaptive thermogenesis.

Glycaemic index ranks a fixed 50 g available-carbohydrate portion against glucose (GI 100); glycaemic load = GI × available carbohydrate (g) ÷ 100, so watermelon (high GI, low load) differs from white bread (high GI, high load).

Nutrient density = nutrients supplied per unit energy; energy density = kJ per gram of food. Water and fibre lower energy density, while fat and added sugar raise it.

Basal metabolic rate typically accounts for 60–75% of total energy expenditure; thermic effect of food is roughly 5–10% of intake, and physical activity makes up the remainder.

Protein quality is scored by digestibility and limiting amino acids (PDCAAS, or DIAAS); cereal proteins are limited by lysine, legume proteins by methionine, so combining them improves the overall amino acid pattern.

Macronutrient roles: carbohydrate supplies glucose and spare protein; protein supplies essential amino acids for tissue synthesis; fat supplies essential fatty acids (linoleic, alpha-linolenic), carries fat-soluble vitamins A, D, E and K, and insulates and protects organs.

Micronutrient reference values: calcium RDI about 1000 mg/day for adults (higher for adolescents and older adults), iron about 8 mg/day for adult men and 18 mg/day for menstruating women, with vitamin C enhancing non-haem iron absorption and phytates and tannins inhibiting it.

Digestion sequence: salivary amylase begins starch breakdown in the mouth; gastric acid and pepsin act on protein in the stomach; pancreatic amylase, lipase and proteases plus bile salts act in the small intestine, where most absorption occurs via villi and microvilli.

Lactose intolerance results from reduced lactase activity, causing osmotic diarrhoea and fermentation by colonic bacteria; it differs from cow's milk protein allergy, which is an immune-mediated reaction.

Coeliac disease is an autoimmune response to gluten peptides that damages small-intestinal villi, impairing absorption of iron, calcium, folate and fat-soluble vitamins; it is not the same as non-coeliac gluten sensitivity.

Diet–disease relationships: excess saturated and trans fat and sodium raise cardiovascular risk; excess free sugars and poor oral hygiene promote dental caries; high fibre intake is associated with reduced risk of colorectal cancer and type 2 diabetes.

Food security has four pillars: availability, access, utilisation and stability; food insecurity ranges from anxiety about supply through to outright hunger and nutrient deficiency.

Food labelling rules: the nutrition information panel must state energy, protein, fat (total and saturated), carbohydrate (total and sugars) and sodium per serving and per 100 g; health claims must meet qualifying criteria, and ingredient lists are ordered by descending weight.

Nutrition assessment uses the ABCD framework: anthropometric (BMI = mass in kg ÷ height in m²; waist circumference), biochemical (blood glucose, lipids, iron status), clinical (signs such as pallor or oedema) and dietary (24-hour recall, food frequency questionnaire, weighed food record).

Adult BMI categories: under 18.5 underweight, 18.5–24.9 healthy range, 25.0–29.9 overweight, 30.0 and above obese; BMI does not distinguish fat from lean mass, so it is interpreted alongside waist circumference and other measures.

The five food groups and recommended proportions: vegetables and legumes, fruit, grain foods (mostly wholegrain), lean protein foods, and dairy or alternatives; discretionary foods high in saturated fat, added sugar, salt or alcohol are limited.

Food processing classification (NOVA): group 1 unprocessed or minimally processed, group 2 processed culinary ingredients, group 3 processed foods, group 4 ultra-processed products; higher group 4 intake is associated with poorer diet quality.

Food systems stages: production, processing, distribution, retail, consumption and waste; each stage affects nutrient content, food safety and environmental impact, and food loss occurs mainly before retail while food waste occurs mainly after.

Food safety: the temperature danger zone is 5–60 °C, with bacteria multiplying fastest around 37 °C; high-risk foods are those high in moisture and protein, such as cooked meat, dairy and seafood.

Fortification adds nutrients to foods to correct a documented deficiency (for example, iodine in salt, folic acid in bread-making flour), whereas enrichment restores nutrients lost during processing.

Sustainable diets aim to meet nutritional needs while limiting environmental impact; strategies include shifting toward plant proteins, reducing overconsumption and food waste, and choosing locally seasonal produce where feasible.